Phase change material composition and method of fabricating and packaging the same

ABSTRACT

A unique phase change material composition and method of maintaining pre-established environmental conditions and safeguards during the manufacturing process. A fabrication method and parameters which result in a more efficient and safe packaged phase change material. A microspherical form of Perlite is the chosen phase change material. The microspherical form of Perlite is vacuum packed in such a manner to exclude water and moisture as well as utilizing a sealing surface of sufficient width to maintain a vapor barrier at the sealed edges. Besides absorption and release of heat, the packaged phase change material may be used as a fire preventive article in residential and commercial properties.

CROSS-REFERENCE

This application is a division of U.S. patent application Ser. No.15/092,438 filed Apr. 6, 2016

FIELD OF THE INVENTION

The embodiments of the present invention relate to packaged phase changematerial composition and method of fabricating the same rendering thepackaged phase change material composition efficient and safe.

BACKGROUND

Phase change materials are able to store heat energy. Phase changematerials are chemical compounds that use latent heat properties of amaterial to store heat energy as chemical energy. Latent heat is ameasure of the energy necessary to change a material from one state toanother. Phase change materials store heat by melting or otherwisechanging from a solid to a liquid and release heat by freezing orotherwise changing from a liquid to a solid.

Phase change materials have long been seen as the answer to reducingenergy loads. Unfortunately, the advancement of phase change materialshas not materialized. There are many reasons, including inefficienciesand safety, for the lack of advancement of phase change materials.

Thus, it would be advantageous to develop a more efficient and safepackaged phase change material composition for use with residential andcommercial buildings.

SUMMARY

Embodiments of the present invention relate to fabrication methods andparameters which result in a more efficient and safe packaged phasechange material compositions. In one embodiment, a microspherical formof Perlite is used as the phase change material. In another embodiment,the microspherical form of Perlite is vacuum packed in such a manner toexclude water and moisture while utilizing a sealing surface ofsufficient width/depth to maintain a vapor barrier at the sealed edges.In another embodiment, the packaged phase change material compositionmay be used as a fire preventive article in residential and commercialbuildings.

Another embodiment of the present invention relates to a phase changematerial composition and method of manufacturing the same. The methodcomprises utilizing a unique composition and maintaining pre-establishedenvironmental conditions and safeguards during the manufacturingprocess.

Other variations, embodiments and features of the present invention willbecome evident from the following detailed description, drawings andclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a phase change pouch of the type used to packagephase change material according to the embodiments of the presentinvention;

FIG. 1B illustrates a series of pouches of FIG. 1A filled with a phasechange material composition joined to a substrate to form a panel ortile according to the embodiments of the present invention;

FIG. 2 illustrates a flow chart detailing a phase change materialcomposition packaging process according to the embodiments of thepresent invention;

FIG. 3 illustrates a flow chart detailing a phase change materialcomposition manufacturing process according to embodiments of thepresent invention; and

FIG. 4 illustrates a block diagram of a system for fabricating andpackaging a phase change material composition according to embodimentsof the present invention.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles inaccordance with the embodiments of the present invention, reference willnow be made to the embodiments illustrated in the drawings and specificlanguage will be used to describe the same. Any alterations and furthermodifications of the inventive feature illustrated herein, and anyadditional applications of the principles of the invention asillustrated herein, which would normally occur to one skilled in therelevant art and having possession of this disclosure, are to beconsidered within the scope of the invention claimed.

Phase change material compositions come in many forms but many are noteffective at absorbing heat and discharging heat as desired. Theembodiments of the present invention are designed to render the phasechange material composition more efficient and effective for thepurposes detailed herein.

Table 1 details an exemplary ingredient list for a first phase changematerial composition according to the embodiments of the presentinvention.

TABLE 1 Weight Purity Material Percentage Level Calcium Chloride 40.08%94%-97% (CaCl₂) Potassium  4.22% >99% Chloride (KCl) Strontium 0.86% >99% Chloride (SrCl₂) Sodium Chloride  1.46% >99% (NaCl₂) BariumSulfate  0.09% >99% (BaSO₄) Water (H₂O) 39.29% purified Perlite 14.00%

While Table 1 details a specific phase change material composition,those skilled in the art will recognize that the weight percentages ofthe ingredients may fluctuate without significantly impacting theeffectiveness of the phase change material composition. For example, inother embodiments, the Calcium Chloride weight percentage may range fromabout 30% to 50%, the Potassium Chloride weight percentage may rangefrom about 3% to 6%, the Strontium Chloride weight percentage may rangefrom about 0.0% to 1.5%, the Sodium Chloride weight percentage may rangefrom about 0.0% to 2%, the Barium Sulfate weight percentage may rangefrom about 0.0% to 1.0% and the Perlite weight percentage may range fromabout 10% to 20%. Other salts may be used as well. U.S. Pat. Nos.4,613,444 and 4,412,931 to Lane which are incorporated herein byreference disclose many salts that may be suitable for the embodimentsof the present invention.

In one embodiment, as set in Table 1, the phase change materialcomposition ingredients have threshold purity levels further renderingthe phase change material composition more effective for the purposesdescribed herein. The phase change material composition manufacturedaccording to Table 1 and the manufacturing procedures set forth belowhas a transition temperature of approximately 80° F. with a latent heatof fusion of 70-80 Btu/lbm.

In one embodiment, a microspherical form of Perlite is the phase changematerial in the phase change material composition. Perlite is alightweight filler material formed from expanded volcanic ore. In oneembodiment, the microspherical form of Perlite is promoted and soldunder the name “Sil-Cell Sil-42.” Perlite known by Sil-Cell Sil-42prevents incongruent melting, provides nucleation sites for formation ofthe hexahydrate form of CaCl₂ during the freezing phase, and providessufficient thickening of the packaged phase change material when in theliquid phase to prevent sagging under gravity when used in a verticalorientation. Sil-Cel Sil-42 is supplied by Silbrico Corporation locatedin Hodgkins, Ill.

Applicant has determined that the introduction of water into the phasechange material composition packaging negatively impacts the integrityof congruent melting and freezing in the phase change materialcomposition. Maintaining the integrity of congruent melting and freezingin the phase change material composition is therefore an objective ofthe embodiments of the present invention. Accordingly, one embodiment ofthe present invention utilizes clean seals and seals which act as vaporbarriers. In one embodiment, the phase change material composition issealed in poly-vinyl-foil laminated pouches 100 as shown in FIG. 1A. Asshown in FIG. 1B, multiple poly-vinyl-foil laminated pouches 100-1through 100-N may be joined to a substrate (e.g., insulation tile) toform a panel or tile 110 of poly-vinyl-foil laminated pouches filledwith phase change material composition. To maintain the effectiveness ofthe poly-vinyl-foil laminated pouches 100-1 through 100-N, the sealsshould 105 be clean and deep or wide enough to form a vapor barrier. Inone embodiment, the seals 105 of the poly-vinyl-foil laminated pouches100-1 through 100-N are at least ¼″ deep from outer edge to the phasechange material composition in the poly-vinyl-foil laminated pouches100-1 through 100-N to form a vapor barrier.

In one embodiment, the thickness of the phase change materialcomposition in the poly-vinyl-foil laminated pouches 100-1 through 100-Nshould be a minimum of 1.25 cm thick. In one embodiment, 6″×8″poly-vinyl-foil laminated pouches are used but those skilled in the artwill recognize that poly-vinyl-foil laminated pouches of other sizes maybe used.

The panels or tiles 110 may then be used in residential or commercialbuildings to maintain consistent temperatures and reduce energy loads asdisclosed in U.S. Pat. Nos. 7,735,327 and 7,797,950 which are bothincorporated herein for any and all purposes.

FIG. 2 shows a flow chart 200 detailing a phase change materialpackaging process according to the embodiments of the present invention.At 205, poly-vinyl-foil laminated pouches are filled with phase changematerial composition. In one embodiment, a hopper with a pneumaticfilling piston is used to fill the poly-vinyl-foil laminated pouches. Inone embodiment, each 6″×8″ poly-vinyl-foil laminated pouch containsabout 250 grams of phase change material composition. Smaller and largerpouches would contain less or more phase change material composition,respectively. At 210, a mouth of the poly-vinyl-foil laminated pouch iscleaned with a cloth if needed. The mouth of the poly-vinyl-foillaminated pouch should be clean from phase change material compositionand other contaminants such that a good seal is formed. At 215, vacuumchambers having heat sealing bars are utilized to seal thepoly-vinyl-foil laminated pouches filled with phase change materialcomposition. In one embodiment, ⅜^(th) of an inch of the poly-vinyl-foillaminated pouch should extend beyond a sealing strip to ensure the sealis at least ¼″ deep or wide. At 220, the seal is inspected for flatnessand straightness. If any part of the seal is folded or improperlyaligned, the poly-vinyl-foil laminated pouch may be ineffective. At 225,seal inspected to determine if any phase change material composition hasmade it past the seal during the sealing process. If not, at 230, thepoly-vinyl-foil laminated pouch is torn open so that the phase changematerial composition is re-used. If the seal is good, at 235, the sealedpoly-vinyl-foil laminated pouches are placed flat on a cooling rack tocool and solidify.

FIG. 3 shows a flow chart 300 detailing a phase change materialcomposition manufacturing process according to the embodiments of thepresent invention. At 305, relative humidity in manufacturing facilitymaintained at <35%. At 310, a salt solution is manufactured. At 315, thesalt solution is added to a Perlite mixing tank. At 320, a proper massof Perlite is gradually added to the salt solution and mixed at lowspeed with the temperature maintained at 100° F.-110° F.

FIG. 4 shows a block diagram 400 of a system for fabricating andpackaging phase change material composition. A scale 405 is used toweigh salts for manufacturing a salt solution in accordance with thepercentages and purity levels set forth in Table 1 for example. A saltsolution mixing tank 410 is used to mix a salt solution. In oneembodiment, the salt solution mixing tank 410 is a 30 gallon cone-bottomtank. Mixing of Calcium Chloride and water is an exothermic reaction.The rapid addition of Calcium Chloride to water in an uncontrolledtemperature environment can lead to temperature rise in excess of 100°F. Calcium Chloride must be added in a controlled manner with activecooling of the mixture. This is achieved via a shell and tube heatexchanger 406 circulating chilled water to remove heat from the saltmixture in the salt solution mixing tank 410. The water-Calcium Chloridemixture is prone to freezing below 80° F., so once the Calcium Chlorideaddition is complete, the system temperature must be held between 100°F.-110° F. A resistive heating blanket 408 around the salt solutionmixing tank 410 is effective at maintaining system temperature withinacceptable limits. In one embodiment, Calcium Chloride is added to waterand run through the chiller to cool, then remaining salts are added withheat to prevent freezing. After the Calcium Chloride and water aremixed, the other salts may be added.

In one embodiment, recirculation is utilized to create an evenlydissolved and mixed salt solution. The granular nature of the saltsposes risks of clogging, slow mixing and imperfect dissolving. A mixer409 is essential to quick and thorough dissolving of salts. In oneembodiment, the mixer 409 is a Silverson High-Shear Inline Mixer/Pumphaving a special rotor-stator workhead configured to apply a shearingaction to a fluid being pumped—helping to mix and break down anysuspended solids. Using the mixer/pump generates both a mixing andcirculating action.

A Perlite mixing tank 415 is in communication with the salt solutionmixing tank 410 via a gravity feed or pump feed. In one embodiment, thePerlite mixing tank 415 is a 60 gallon cone bottom tank. The contents ofthe salt tank, once mixed, are pumped or drained into the clean, dryPerlite mixing tank 415 prior to addition of the Perlite. As referencedherein, to create the most effective phase change material, the Perliteand salt solution must be in a specific ratio. For every kilogram of thesalt solution, a specific mass of Perlite must be added. Once the properamount of Perlite is calculated, the Perlite may be added in two ways.First, the needed mass of perlite and the known mass of the saltsolution can be added to find the total weight of the final product.Perlite can then be added to the salt solution, and the mixture may beconstantly measured until the target mass is reached. Second, in analternative manner, the needed mass of Perlite can be weighed in asingle container. The measured amount of Perlite can then be added tothe salt solution. In one embodiment, the Perlite mixing tank 415 restson a scale 411 to permit proper weights of salt solution and Perlitemass. A heat blanket 417 may be used to maintain desired temperatures inthe Perlite mixing tank 415.

The Perlite should be added gradually, at a temperature of 100° F.-110°F., to prevent large piles/groupings of Perlite on a surface of themixture.

Perlite is a friable material, which when expanded from volcanic ore,forms a “glass” bubble. During the mixing process, the Perlite may begrounded or sheared. Accordingly, Perlite should be mixed at lowerspeeds with less aggressive mixing methods. In one embodiment, thePerlite mixing tank 415 incorporate a ribbon mixer 416. A gentlechurning or folding action is ideal.

A hopper 425 receives phase change material from the Perlite mixing tank415 by means of a diaphragm pump 420. Since Perlite is much lighter thanthe salt solution and tends to separate to the surface of the mixture,the Perlite tank 415 and the hopper 425 should be constantly mixed, orregularly and consistently mixed. A vacuum-sealing machine 430 isutilized to thermally seal the phase change material composition thepoly-vinyl-foil laminated pouches 100-1 through 100-N of the type shownin FIGS. 1A and 1B.

The filling and sealing of the poly-vinyl-foil laminated pouches 100-1through 100-N then occurs as described above relative to FIGS. 2 and 3.In one embodiment, the phase change material composition comprising thesalt solution and Perlite is manually dropped into the poly-vinyl-foilpouches 100-1 through 100-N via hopper 425. The process may also beautomated.

Although the invention has been described in detail with reference toseveral embodiments, additional variations and modifications existwithin the scope and spirit of the invention as described and defined inthe following claims.

I claim:
 1. A method of manufacturing a phase change materialcomposition comprising: (i) mixing salts consisting of about 30%-40% byweight of Calcium Chloride with about and 30% to 50% by weight of waterwith about 3.0% to 6% by weight of Potassium Chloride; (ii) adding about10% to 20% by weight of Perlite to said mixed salts; (iii) mixing saidPerlite and said mixed salts; (iv) maintaining a relative humidity of<35% during steps (i) through (iii) and optionally further comprising insteps (ii) adding 0.01% to 0.3% by weight Barium Sulfate, 0.1% to 1.5%by weight of Strontium Chloride and/or 0.1% to 2.0% by weight of SodiumChloride.
 2. The method of manufacturing of claim 1 further comprisingin step (ii) adding Perlite in microspherical form.
 3. The method ofmanufacturing of claim 1 further comprising maintaining a temperaturebetween 100° F.-110° F. during step (iii).
 4. The method ofmanufacturing of claim 1 further comprising in step (ii) graduallyadding Perlite until a desired Perlite mass is reached.
 5. The method ofmanufacturing of claim 1 further comprising causing a desired amount ofphase change material composition to be added to a poly-vinyl-foillaminated pouch.
 6. The method of manufacturing of claim 1 furthercomprising in step (i) cooling said mixture of salts to maintain adesired temperature during the mixing of Calcium Chloride and water. 7.The method of manufacturing of claim 6 further utilizing a heatexchanger for cooling said mixture of salts to maintain a desiredtemperature during the mixing of Calcium Chloride and water.
 8. A methodof manufacturing a phase change material composition comprising: (i)mixing salts consisting of about 30%-40% by weight of Calcium Chloridewith about and 30% to 50% by weight of water with about 3.0% to 6% byweight of Potassium Chloride; (ii) adding about 10% to 20% by weight ofPerlite to said mixed salts; (iii) mixing said Perlite and said mixedsalts; (iv) adding desired amounts of phase change material compositioncreated in steps (i) through (iii) to poly-vinyl-foil laminated pouches;(v) sealing said poly-vinyl-foil laminated pouches such that said sealsare at least ¼″ wide; (vi) maintaining a relative humidity of <35%during steps (i) through (v) and optionally further comprising in steps(ii) adding 0.01% to 0.3% by weight Barium Sulfate, 0.1% to 1.5% byweight of Strontium Chloride and/or 0.1% to 2.0% by weight of SodiumChloride.
 9. The method of manufacturing of claim 8 further comprisingin step (ii) adding Perlite in microspherical form.
 10. The method ofmanufacturing of claim 8 further comprising maintaining a temperaturebetween 100° F.-110° F. during step (iii).
 11. The method ofmanufacturing of claim 8 further comprising in step (ii) graduallyadding Perlite until a desired Perlite mass is reached.
 12. The methodof manufacturing of claim 8 further comprising in step (i) cooling saidmixture of salts to maintain a desired temperature during the mixing ofCalcium Chloride and water.
 13. The method of manufacturing of claim 12further utilizing a heat exchanger for cooling said mixture of salts tomaintain a desired temperature during the mixing of Calcium Chloride andwater.
 14. The method of manufacturing of claim 8 further comprisingcleaning a seal area before step (v).